* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html ,body{
    height: 100%;
    background: url(../pic/taiji.jpeg);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
}
.nav{
    height: 55px;
    line-height: 55px;
    background-color: rgb(184, 173, 181);
    color: rgb(110, 100, 100);
    padding-left: 20px;
}
.container{
    height: calc(100% - 55px);
    display: flex;
    justify-content: center;
    align-items: center;
}